The insipid slushfest Diana hits DVD this week, but a more galvanising portrait of the late princess is to be found online, where fervent analysis of her untimely demise continues apace. Last month, the web's already extensive collection of Diana exposés grew three sizes stupider overnight when Unlawful Killing – a long-unavailable 2011 documentary funded by Mohamed Al Fayed and directed by 90s irrelevance Keith Allen – found its way on to YouTube. Given the overwhelming clunkiness of the finished product, you suspect that the bulk of Al Fayed's reported £2.5m investment was spent finding anyone who'd be willing to lend their names to the project. All the key players refused to be interviewed, so instead Allen fell back on great thinkers of the age such as Piers Morgan and Howard Stern. Beyond their enlightening input – and seriously, you haven't heard the word "establishment" until you've seen Morgan spit it out between a pair of gestured quote marks – Unlawful Killing is a mess of wild conjecture and overblown montage. In one memorable sequence, Allen solemnly describes the "strangely melancholic effect" that Diana's death had on him, before segueing into a montage of slow-motion archive material set to to UB40's cover of (I Can't Help) Falling In Love With You. Following a single trade screening at the Cannes Film Festival, the film found itself permanently shelved after lawyers insisted on no less than 87 edits to its 78-minute runtime, with Prince Philip among those being libelled. Frustrated, Allen wrote a piece for the Guardian bemoaning the film's fate, and blaming online commentators for their part in the fiasco. The internet, he said, was "a global lavatory wall, a Rabelaisian mixture of truth, lies, insanity and humour". By that definition, Unlawful Killing may finally have found its spiritual home.